Marginal pond planting shelves:
When you build your pond create the right depth shelves into your construction.
- Build the majority of planting shelf at 6 – 8″ depth below finished water level. A smaller area of 12″ shelf and a base of 2’6″ (or 15 – 20cm, 30cm and 75cm).
- For a wildlife pond have a beach or sloping area with cobbles and shallow loving plants
- For a plant or a wildlife pond 2/3rds of the pond should be shelved at various depths with 1/3rd of the area being at the deepest level. This gives the right proportions of space for plant and wildlife use.
- A fish orientated pond would need more deep area of 3-4′ (90-120cm) – 1/2 deep water and 1/2 shelved.
As a guide we recommend a minimum of 3 x 1 litre marginal aquatic baskets per metre length on a shelf, with more if the shelf is wider than 30cm(12″) or if a full look is required quickly.
Water depth is vital to marginal pond plants – too deep and one variety will not thrive, too shallow and some varieties will not receive the frost/ice protection over their crowns that they would receive from deeper water.
Plants that sit with their crowns at/near water level – on an exit slope or shallow shelf of up to 5″ deep. These plants will will be happy with their roots in water but with little or no water over their crowns. These plants could also grow in wet mud in a muddy bog garden or on a stream edge with their crowns exposed above water level or in a floating pond basket.
Plants for a shallow 14 – 22cm(6-9″) depth shelf – your pond should contain a mix of both upright and rafting plants to create the habitats different wildlife will enjoy. These plants are listed in the pond plant pages as accepting up to 10cm(4″) of water over the top of the basket.
Plants for a deeper 23-44cm(10-17″) depth shelf – some plants enjoy a deeper shelf that will place the crown of the plant in deeper water throughout the winter where there is little risk of ice penetrating the pond to that depth. These plants are also on the Pond plant pages. Dwarf waterlilies also come into this section as they will not grow from as deep water as the more vigorous Pond waterlilies.
2 portions of oxygenating plants should be added to a new pond per square metre of surface area and aim for at least 50% of your water surface area covered by plant growth to keep the water cool and shaded.
For more details read our Tips and Advice pages: How to dig an informal pond